Cover Crops, a Farming Revolution With Deep Roots in the Past

Dan DeSutter, in a field of dried-up daikon radish, sunflower, turnip and hairy vetch, has been experimenting with cover crops for 17 years.

This article is for all the skeptics out there. There is a way for soil remediation done in a natural way. When Mark Anson came home with his hair on fire after a seminar on the seemingly soporific topic of soil health, his younger brother, Doug, was skeptical.

What had Mark lit up was cover crops: fields of non-cash crops like hairy vetch and cereal rye that act on soil like a nourishing facial after the harvest.

Mark, 60, and his two brothers, together with assorted sons and sons-in-law, run Anson Farms, a big commercial soybean and corn operation in Indiana and Illinois. Concern about the soil quality of the family’s fields had nagged at him for some time. “Our corn was wilting when temperatures hit 103 degrees,” he said, and such heat isn’t so unusual in the summer. “I felt like I had a gorilla on my shoulder.” What he learned about the benefits of cover crops gave him hope.

But to Doug, planting some noncommercial crops seemed an antiquated practice, like using a horse-drawn plow. Cover crops had long been replaced by fertilizers. Still, he shared his brother’s concern about their soil. Its texture was different, not as loamy as it had once been, and a lot of it was running off into ditches and other waterways when it rained.

Dan DeSutter’s 5,000-acre farm near Attica, Ind. Credit David Kasnic for The New York Times

So in 2010 the family decided to humor Mark by sowing some 1,200 acres, which Mark describes as highly eroded farmland, with wheat cleanings and cereal rye. Additionally, they spread some cover crops to eroded areas in a few fields.

The next spring, Doug had to admit that the soil texture on that strip was better. And the water that ran off it during a rainstorm was clear, a sign that the roots of the cover crops were anchoring valuable topsoil in place.

But Doug didn’t become a believer until 2013, when the family was grappling with a terrible drought. “In the part of a field where we had planted cover crops, we were getting 20 to 25 bushels of corn more per acre than in places where no cover crops had been planted,” he said. “That showed me it made financial sense to do this.”

Now some 13,000 of the 20,000 acres that the family farms across nine counties are planted with cover crops after harvesting, and farmers around them are beginning to embrace the practice.

Cover crops are coming back in other areas of the country, too. The practice of seeding fields between harvests not only keeps topsoil in place, it also adds carbon to the soil and helps the beneficial microbes, fungus, bacteria and worms in it thrive.

These properties have led philanthropies like the Howard G. Buffett Foundation and the Samuel Roberts Noble Foundation to underwrite research on cover crops, while Monsanto, together with the Walton Family Foundation, recently put up the money to support the Soil Health Partnership, a five-year project of the National Corn Growers Association to identify, test and measure the impact of cover cropping and other practices to improve soil health.

Cover cropping is still used only by a small minority of farmers. When the Agriculture Department asked for the first time about cover cropping for its 2012 Census of Agriculture report, just 10.3 million acres — out of about 390 million total acres of farmland sown in crops — on 133,124 farms were planted with cover crops. The next census won’t be done until 2017, but experts say that the practice has spread. In an annual survey of about 1,200 farmers, the mean acreage reported as being sown in cover crops was 259 in 2014. That was double the mean reported by respondents in 2010, though results are not directly comparable because different farmers may have been involved in the surveys, said a spokesman for the Sustainable Agriculture Research & Education, a federal government program, which conducted the survey.

“We’ve never seen anything taken up as rapidly as using cover crops,” said Barry Fisher, a soil health specialist at the Natural Resources Conservation Service, an agency within the Agriculture Department.

“We’ve concentrated on the physical and chemical aspects of farming but not the biological,” said Mr. DeSutter, an Indiana farmer who has experimented with cover crops. Credit David Kasnic for The New York TimesInterest in cover crops is coming from buyers, too. Dan Barber, a prominent chef who uses locally grown foods, has championed incorporating cover crops like clover and millet into cuisine as a way of encouraging farmers to grow them.

The Blue Ox Malthouse in Maine was established to coax farmers there to grow barley as a cover crop, which the company then turns into malt that is sold to the state’s craft beer industry. Half a dozen farmers are producing good-quality barley as a cover crop, and others “are interested in turning the grains they’ve been growing as cover crops into something there’s a value-added market for,” said Joel Alex, Blue Ox’s founder and maltster.

One measure of how rapidly the practice is growing is the booming demand for cover crop seeds. Keith Berns, a fourth-generation family farmer in central Nebraska, started making cover-crop seed mixtures in 2010, and the business “just kind of took off,” Mr. Berns said.

He and his brother, Brian, turned what started as a hobby into a thriving enterprise. This year, Green Cover Seed, their company, will sell enough seed to cover 500,000 acres in cover crops.